Telephone system



June 10, 1930.. 1,762,778

TELEPHONE SYSTEM Filed March 14, 1929 2 Sheets-Sheet l INVENTOR L]. R.GOULD A TTOR/VEV June 10, 1930. J. R. GOULD TELEPHONE SYSTEM Filed March14, 1929 2 Sheets-Sheet 2 INVENTOR J. R. GOULD ATTORNEY w I ilowestfirst'digit of the. four-dlglt numbers,

final selectors which give access to groups of lines having five-di gitnumbers.

The apparatus and wiring shown in Figs. 1, 2 and 3 providedistributorfacilities for giving the trunk-offering operator at A accessto offices in which all of the lines have "five-digit numbers and to oflices, in which some ofthe lines have tour-digit numbers I r and somehave five-digit numbers providing '10 that the four digit numbers andthe fiVe-digit numbers always differ in the first twodigits runconsecutively.

digits and their total does not exceed 10,000

c eed 20,000 i. e. 19,000-59,999.

3000- i. e. 4t9,00058,999.

0 i. e. 2000-4899. The five-digit numbershave two difierent firstdigits, of which one may p having the called number.

or may notbe the same as the highest or the andtheir, total exceeds10,000 but does not eX- having both four-digit and five-digit numbers.The four-digit numbers have different first digits and their total. doesnot exceed 10,000. i; e. 20004899. Thefive-digit numhere have twodiiierent first digits, of which one may or. may not bethe same asthehighest'or the lowest first digit ofthe four-diglt numbers, and theirtotal does not exceed 10, (a) Oifices having both four-digit andfive-digit numbers. The

four-digit numbers have different first digits and their total does not8XC86d-10,000 1. e.

' 2000-4899. All five digit numbers have the .f same first digit andthis digit'is either the highest or the lowest ot the first digits ofthe fou'rdigit numbers i. e. 49300 42009. 'The total of both'four-digitand five-dlgit numbers does not exceed 10,0003 (cl) Oflices havi ingboth four-digit" and five-digit numbers,

the first digit of, all numbers being the same (as in 'ainain Office andits satellites) i. e.

6100'i6699, ;and 61000-699993 =The"tota1 of all numbers does not'eXceed10,000 (6) Of- "ficesin which all numbers are five-digit numbe rs andtheir total does not exceed 10,000

-eonoo, -i. e: sumo-62,999:

"lThe operation" of the circuits. shown in Figs; land. 2 for giving thetrunk-offering operator. at A'accessto an office otthe above ":mentionedclassta) will now be. described 1 in detail. In such an ofiice the lineshaving {[four-'digitjnumbers, i. e. from 2000 to 4899' inc1usive, a reaccessible ,tl1rough sets of ter-' minalsin' the bankof switch S; lineshaving 'fiveedigit numbers whose first digit is the ysameas the firstdigitof some f-of the four l I digitnumbers, i. e. from 49,000 to 9,999in-' f clusive, are accessible through sets of termi- "nals in'the'bankof switch M, and the. lines the line of the called number.

having five-digit numbers whose first digit is different from the firstdigits of the fourdigit numbers, i. e. from 50,000 to 59,999 inclusive,are accessible through sets of terminals in the bank of switch T. \Vhenthe first digit of the called number is dialed the brushes of switches Mand S are stepped up to the corresponding level. The shaft and brushesof switch M are then returned to normal and the pulses Originatedby thedialing of the second digit step the brushes of switch M in a verticaldirection and at the same time step the brushes of switch Sin arotarydirection into contact with the cor responding set of terminals in thepreviously selected level. If the. called number is a four-digitv numberthe terminals with which the'brushes of switch S are in contact connectwhich the brushes of the switch S are in contact is permanentlyconnected through a high resistance to battery, this arrangement bemgeffective to prevent the further operation of switch S. Wh'en 'theIthirddigit of the called number is dialed the brushes of switch M are steppedin a rotary direction intocontact with a set of terminals which connectto a final selector having access to If the number isa five-digit numberwhose first digit is different from the first digits of the fourdigitnumbers level-springs NP are actuated when the brushes of switch M arestepped up to that level and the further operation of switches M and Sis thereby prevented. Thereafter switch T, only, is actuated inresponseto the dialing of the second and third digits of the callednumber to advance its brushes into contact with. a set of terminalswhich connect to a final selector having access to the line of thecalled number. (For an oifice within class (a) the'NPA springs and Fig.3 are omitted.)

WVhen the operator at A inserts plug 7 in Relay 5 in the of jack 8 -Relay & in the cord circuit and relay 12 in the distributorcircuit areoperated in an obvious circuit over the tip side' of the trunk. Relay 14in the distributor circuit operates over the ringside of the trunk in a:circuit which may be traced-from grounded battery through one winding iof the repeating coil and through the normally closed contacts of dialkey'l in the cord cir cuit, over the ring side of the trunk 9,

through the winding of relay 14:, lead 19, normally closed" contact-sof'the vertical offnormal springs 220',- 1:20am 20 of switches T, SandM, respectively, back contact and right handarmature-of relay'35,andthrough .the normally closed contacts of the continuity springs of relay15, to gronnd.- The opera tion o tfrelay 142 closes an-obviouscircu'itfor r operating relay'15', Theoperationof relay 15 connectsground through: the normally Vopen' entacts, ofitscontinuity springs'di-f springs of switches M, S and T1 Afteroperatingidial' key 1, thetrunli-ofiering-operator {llfilSfthGIlllHlbOf of thesubscribersvstatio'nwith which c'on'nection'is de-' sired. Theo'peration'of the dial 2' opens and closes the circuitrover theringsidecf trunk 9 thereby causingthealternate release. and reoperation ofrelay 1d. Relay 1s a: slow to release relay and. therefore it does notrelease cluring dialing; The first releaseof right-hand 'a-rniature ofrelay-115, back contact and next to-the-imier,right hand;armav tin-e01relay 36-, normally closed contacts of Y 7 V the continuity, springs ofrelay -16, andthrough the macaw-event springs 18,-t0 Y relay 1 1: causesthe operation of relay 16,3ver4 tical stepping magnet 27 of switch M,and

vertical l stepping magnet 12'? of. switch- .8.

The circuit for relay 16 may betraced from batte ry throngh. itswinding, lead 17, front contact and inner right-hand,armature of relayl5, back'conta'ct and innerrrg'ht-hand 'annature-ot relay 14, toground'.The clrcuit for vertical] ma'g'neti27 may be traced from batterythrough: its winding, back contact and inner left-hand armature of relay2.30, back contact and neXt-to the-Onter right-hand armature of relay33, back. contact andinner *righthand arn-ratureofrelayhmmiddlelefthand: arinature'jandback Contact or-ien ee,

,lnidd'l'e" lower armature and back contactof relay 34", tozgrcund onlead, 17, The circuit tor-vertical; magnet 1 27- niaybe traced troinbattery? thrdu gh its: -winding,'- back: contact- -and 'outer right-handarinature of relayr36, outer right-handar1nature ancl ba ck con-- I tactof relay 14, back contact andneXt-to-the- I inner righthandarmaturelofrelay SZ'and through the front contact and neXt-to-the innerright-hand:arni ature *ofrelay 15, to' groii nd, Relay 126 is also a:slow=toarelea se relay and therefore it does not release. until of thepulses: originated by the. dialing of any one digit have all beenreceived. The" vertical magnets 27 and 127 operate and re 'lease eachtime relay 14L releases and reoperates-thusstepping the brushes'oiiswitch Mend the brushes of switch S up to the level I Whichcorrespo'ndsto the first digit of the 7 called v number; The vertical o lhnormalsprings of switchesandiS are operated assoon astheir' shaftsfare stepped"outof the'ir normal positions, Relay 36 which is'atwose stage relay 'rs'partlally operat'cdin a-circult from batterythrough its left-handwinding, backcon'tact and middle right-hand armature, contact of the VONsprings-18, to

groundon lead 19. When thus partially operated a circuitis closed frombattery through irracircuit which may be'tracedfirom batteryythreughgitswinding, backcontact and right-hand armature ofrel'ay 31, normally 1closed contactsof the continuity springs of relay 16-, c0ntacts otVONsprings 18 to ground; on lead 19w The operation of relay i530 atTthistimeperfornns no useful function, The release of relay 1'6-alsocausesthe oper inumber,

and rushes of: switch Marereturned to nor- I Tmal'as hereinafterdescribed-i I a WVhen relay 16 releases after all off the pulsesoriginated by the dialing. of the first digit; have been received, relay80 operates? 5 ationiof release magnet-29 of switch Min la circuit whichmay bet-raced, from batteryvr35 1 through its Winding,front'con'tactancl outer:

ground on lead 19 j The shaft, brushes,- and --VON- springs of switchMara-therefore, re- 7 .turned-to'normal, thus causing the' release ofrelay 30'andthe-complete operationfofrelay fifirtl'n'ough bothwindin-gsin series to ground at relay 15;

- M up to the level corresponding to the second'digit, and the rotarymagnet 128 01? switch Sis operated to-step the brushes oi switch- S intocontact with the corresponding 'set: of terminals-lathe previouslyselected I I level; Thezcircuit for operating. the rotary I, 'v 1nagnet-128 of; switch S may-be traced from v 7 battery through its winding,front contact and outerright-hand armature of relay 36,- outerfright-hand armature and back; contact oifrelay, 14, back contact andnext-to-theinner right-hand armature of relay 37, to r u d tflrelayfl5iRelay16-releases when all of the pulses originated bythe dialing of, Ithe" second digit have, been a -received,-, thereby operatingrelay 30 ashereinbefore described."

If'theseconddigitisoneiwhichscharacter izes the called number as beingatour-d1g11tt120 brushes 121 122, 12 3, 124-, 125. and 126 are'inrcontact with aisetoi terminals wliich: connect to a.:linal-,selector. If this lector is busy brush -124l1e-ncounters a busypotential o l-the terminal with which it is inner-125 contact, this"terminal being] connected through a low resistance to battery as a busypotential} In'this event relay 37 is operated 'in'a circuit from thisbusy potentiah'through I v brush 124, back contact and innerright-handgewq' armature of relay 16, left-hand armature,

back contact, and left-hand Winding of relay 37, to ground. Relay 37locks through its left-hand armature and back contact of relay x 33, toground at relay 15. Relay 32 operates in this circuit and locks tobattery through its own continuity contacts. The operation of relay 32connects the ring side of trunk 9. through condenser 11, front contactand nextto-the-outer left-hand armature of relay 32, next-to the-innerleft-hand armature and back contact of relay 33, and through condenser40 to the secondary Winding of busy tone transformerBT. Busy tone isthereby transmitted to the trunk-offering operators cord circuit at A, r

If the final selector (which is connected to the set ofterminals Withwhich the brushes of switch S are in contact) is idle the brush124 doesnot encounter a busy potential and re- I lays 37 and 32 are notoperated. In this event relay 31 is operated in a circuit frombatterythrough its Winding, back contact and outer right-hand armature of relay37, front contact and inner right-hand armature of relay 36, backcontact and outer right-hand armature of relay 16, front contact andouter righthand armature of relay 30, contacts of the VON springs 18, toground on lead 19. Relay 31 looks through its front contactsandrighthand armature and through the normally closed contacts of thecontinuity springs of "-540 relay 16, to the same ground on lead 19. The

, operation of relay 31 causes the release of relay 30. Vith relay 30released a circuit is "closed from battery throughthe Winding of relay33, back contact and neXt-to-the-inner left-hand armature of relay 32,front contact and outer left-hand armature of relay 31, back contact andouter right-hand armature of relay 30, and through the contacts of VONsprings 18, to ground on lead 19. Relay33 operates in this'circuit andlocks through its front contact and inner left-hand armature, to thesameground. The operation'of relay 33 causes the operation of relay '35in an'obvious circuit, and connects the pulsing circuit (through brush126) to the vertical magnet (not shown) of the final selector, connectsbusy (low resistance battery) potential through its outer left-handarmature and front contact to brush 124, connects the Winding of testrelay 32 through brush 123 to the sleeve brush of the final selector,and causes the operation of relay 37 in a circuit from batteryrthroughthe outer left-hand armature and front contact of relay 33, back contactand inner right-hand armature of relay 16, and through the lefthandarmature, back contact, and left-hand Winding of relay 37, to ground.Relay 37 locks through its right-hand Winding to ground at relay 15.

7 When the third digit of the four-digit number is dialed relays 14, 15'and 16 function in the same manner as When the first digit was dialedand the vertical stepping magnet (not shown) of the final selectorisoperated to step the brushes of the final selector up to the corresponding level. The circuit for this vertical magnet may be tracedfrom brush 126,

throughthe front contact. and neXt-to-theouter right-hand armature ofrelay 33, back contact and inner right-hand armature of relay 30, middleleft-hand armature and back contact of relay 32, middle lower armatureand back contact of relay 34, to ground on lead 17. The operation ofrelay 16, on receipt of the first pulse, causes the release of relay 31and the release of relay 16, When all of the pulses originated by thedialing of the third digit have been received, causes the reoperation ofrelay 30. Relay 31 cannot noW reoperate through the contacts of relay 37since relay 37 is operated.

When the fourth digit of the called member is dialedrelays 14,15 and 16function in the same manner as when the first digit Was dialed and therotary stepping magnet- (not shown) of the final, selector is operatedto step the brushes of the selector into contact with the set ofterminals to Which the line of the called number is'connected. Thecircuit for operating the rotary stepping magnet is traced from brush125, through the front contact and next-to the-inner righthand armatureof relay 33, front contact and inner. right handoarmature of relay 30,to ground as traced for the operation of the vertical magnet. Theoperation of relay 16 closes a holding circuit for relay 30 and anoperating circuit for relay 31. The circuit for holding relay 30 may betraced from battery through its Windinggfront contact and left-handarmature, and through the middle right-hand armature and front contactof relay 16, contacts of VON springs 18, to ground on lead 19. Thecircuit for operating relay 31 may be traced from batterv through itsWinding, front contact and outer right-hand armature of relay 16, frontcontact and outer right-hand armature of relay 30, contacts of VONsprings 18, togroun'd on lead 19. When relay 16 releases after all ofthe pulses originated by the dialing of the fourth digit have beenreceived, relay 30 is released and relay 31 is looked through its frontcontact and right-hand armature, and through the nor mally closedcontacts of the continuity springs of relay 16, to ground on lead 19.Relay 30 is slow to release so that the release of relay '16 closes acircuit from battery through the Winding of relay 34, front con 7 mo etactand inner right-hand armature of relay 33, front contactandinnerleft-hand arn1a-: ture of relay 31,-backcontaot and outerrighthand armature of relay l 6,'front contact and .outer right-handarmature of relay .30,. con-Y tacts of VON springs; 1 8,'to groundonlea'd 19. Relay 3% operatesin this circuit connect-. 1 ing. the tipandrings sides of trunk 9,th rou ghcondensers. and 111, front contacts andupper arniatures vof relay 34, brushes 121 and 122, and through thebrushes of final selectorf F; to the line or" the called station-B.[Relay 34 locks through its front contact and inner. lower armature andzthroughthe front con 5 tact and inner left-hand armature c' -frelay33, contacts of-VON springs l8,-to ground n'er right-hand armature andback contact-of relay 16', and through the front'contact andouterleft-hand armature, ofrelay 33, tobat: tery. If the called line is'busy' (which it is,

7 since this is aftr unlr-oiiering call) the sleeve 7 brush of the final'selectorencounters a busy (ground) potential and relay 32 operates'lnthe busy test circuit. Relay32locks through its-front contact andright-hand armature,

.terminal of theline andtest relay 32 is re- -leas'es relay 12it' not'alrea dyreleased; "The- 551:" release of relayle opens the eircuitior'relay of switches.

holds the circuit for-relay 12 closediafterrelay 341 has operated, andcloses a loop through V resistance 41 acrossthe tip and ring leads from.the final selector. r

The trunk-oiiering operator nowofiers the waiting trunk call to: the.called subscriber When the subscribers release the connection.n'rhi'ch'has been holding the called line busy,

the busy potential is removed from the sleeve leased. The releaseo'f-relay '32 disconnects relay 12" from the tip si'deoftrunk 9, therebycausing the releaseof relay 4 and the con-x 7 sequent" lighting ofsupervisory-lamp 6 111 the operators cord circuit.' Whenthe operator.removes the plug 7 from jiacki8, relay 5 releases and lamp 6isextingui'shedr The trunk call is then completed overthe regular trainThe removal of relay 14 in the distributor circu tand also're- 15.; Therelease Io-iif relay 15' disconnects ground from relay 14 therebypreventing the reoperation of relay'launtilthe release of thedistributor switches has beencoinpleted. The

: release of relay 15 also disconnects ground froln'lead- 19 therebyreleasing relays 34, 33, 32 and 31 itoperated. If relay 33wasfopera-ted, before release of the'distributor circuit, relay 35 wasalsooperated and relay 35 nowholdsin a circuit from ground at the plug 7from; jack 8 releases normallyclosedcontacts 01trelay 15, through thearmatureiront contact and right-'hand 'windingofrelay- 35', brush 1%,winding of the.

final selector; to-battery.- The release magneto-"lthe release ina'ne't' not shown or" too selectoroperates tliiscircnit'causing theretu'rn-ofthe final selector to-norn'ial. When they sh'ai't ,and brushesof ztheselec'tor reach V "the r. normal po's1t1onthe circuit through] Vthe release magnet and winding' of relay 35 is opened; Therele'aseo'frelay 35 causes the 'operation of release magnet 29 of switch MI ina. circuit fronibattery through its winding, contacts of VON springs 20,biackcont'act and armature of relay 35,'to ground at relay 1f andbrushesot switch M tonorinal," thereby 'Thc-operati'on ofInagn'et29returns the shaft '-i opening the circuit of release magnet 29at springs 13 and 18 are also returned to their normal positions. lVi-thswitch M normal,

the release magnet'lQQ of switch S operates in a circuit through thefront contact of VON springs andthroug hthe norn'xa'lly closed contactso'f'VGN springs 20, to ground asde SClTlbQCl for operatingv magnet 29;tion of magnet 129 returns the shaft and the contacts of VON springs-20pVON brushes ofswitch S to normal, thereby openingthe circuit o f'releaseinagnet129.- With the VON sprin gs12O in their normal position groundis, connected 'tosthe winding of relay I 14 in readiness for anothercall.

If the'isecond'diget oi the called number were such "'asto characterizethe nuiniher as being .a five digi trnumber insteadjof a toxin 7 digitnumber ZLSVy'flS assiinied'in' the iore oin'g a description, 'th'eset'ofi'terininals, with which oped into thebrushes 61 switchShave been steasv contact, do; not connect to a ,final selector, and

thev brush 124i encounters ,a' shighf resistance? battery potentialwhleh is eilective to operat relay 37, [as hereinbe fore described andassoon as relay 1 6 releases after all oi? the pulses originated-by thedialingof the 'seconddigit have vbeen received; Relay 3'? locks through.

its right-hahdwinding' to ground at relay-l5 1 and! connects the windingof testrelay 32 50 brush 12 1-?hiit relay 32 is'ni naland dot notoperate since the circuit throughfhr-ush 12 1 is traced tobatterythrough a highresistance. r The-op'erationofrelay alsopreventsthefurtlrer operation of switch S when the third, fourth and'fifthdigits are dialed,

lVhen'the third digit isjdialed relays 14, 15

and 16 function in thesanie manner as when thelirst digit was dialedandthe rotarystep ping niagnet 28 of'switch lllisope'rate'd to advance thebrushes ofiswitch M into'contact with the'correspondi-ng set ofterminals which 7 connect to'a final selector having-access to the l1neofthe called number. The operation of,

relay '16, on'receipt 01" thefirst pulse; closes I I the holding'circuitfor relay 30 and the operating 'circuitfor relay 31., both of thesecircuitshaving been. traced ini the foregoing de- 90 The operafpotent1al battery through a low res1stance scription. When relay 16releases'after all of the pulses originated by the dialing of the thirddigit have been received relay 30 releases but relay 31is locked toground on lead ,19. The release of relay 30 closes the circuithereinbefore described for operating relay 33. Relay 33 looks, closesthe circuit-foreperating relay 35, connects the pulsing circuit throughbrush 26 to the vertical magnet (not shown) .of the final selector,connects busy through its outer left-hand armature and front contact tobrush 2 1, and closes a circuit "frombattery through its outer left-handfive-digit number are dialed, the distributor circuit functions the sameas when the third and fourth digits of the four-digit number weredialed, as hereinbefore described, except that the various circuits toand from the final selector pass through brushes 21, 22, 23,524, 25 and26 of switch M instead of throughbrushes 121, 122, 123, 12 1, 125 and126 of switch S.

If the first digit of the callednumber is j one which characterizes thenumber as being a fivedigit number, level springs NP are ,actuated whenthe brushes of switch M are stepped up to the corresponding level. (If

- the five-digit numbers have different first digits which arenot thesame as any of the springs are actuated on eachofthe correfirstdigits ofthe four-digit numbers the NP sponding levels). lVhen relay 16 releasesafter all of the pulses, originated by the dialing of the first digithave been received, relay 80 is operated and relay 36 is partiallyoperated as, hereinbefore described. The release of relay 16 also closesa circuit, for operating relay- 3?, which is tracedfrom battery. throughthe right-hand winding and normally closed continuity contacts of relay3'l',through the contacts of'NP springs 38, back contact and nextto-the-outer right-- hand armature of relay 36, normally closedcontinuity contacts of relay 16, contacts of VON springs 18, to groundon lead 19. Relay 37 operates in this circuit and locks through the samewinding and through its front cont-act and inner ri ht-hand armature, toround at relay 15. The operation of relay 3; prevents the furtheroperation of switch S when the remaining digits of the called number aredialed. The release magnet29 of switch M operates, when relay 16releases, to restore the shaft andbrushes of switch M to normal ashereinbefore deground as traced for magnet 2?.

1s a two-stage relay and is partially operated scribed. Relay 3Oreleases and relay 36 is completely operated and locked whenithev 27 and227 of switches M and T are operated in parallel to step theirrespective sets of brushes. The circuit for magnet 2'? is the same ashereinbefore traced and the circuit for magnet 227 is from batterythrough its winding,- right-hand winding of relay 230, and through theneXt-to-the-outer right-hand armature and front contact of relay 87, toRelay 230 in this circuit to close a circuit through its left-handwinding and locking contacts.

\Vhen the shaft of switch M is stepped out of its normal position by thedialing of this I second digit the circuit through the left-hand windingof relay 230 is closed at the contacts of VON springs 18, thus causingthe complete operation. of relay 230. The complete operation of relay230 opens the circuit of stepping magnet 2? of switch M topreventthefurther operation of switchM so that the remaining'pulses originatedby the dialing of the seconddigit are efiective to step the brushes ofswitch T, only, to the corresponding level. When relay 16 releases afterall of the pulses originated by the dialing of the second digit havebeen received relay 30 operates to transfer the pulsing circuit fromvertical stepping magnet 227 to rotary stepping magnet 228 of switch T.

when the ulna digit of the called number is dialed relays 14, 15Iand16and rotary magnet 228 function to advance the brushes 221, 222, 223, 221, 225 and 226 of switch T into contact with the corresponding set ofterminals which connect to a' final selector having access to the lineof the called number. Relay 31 is operatedand relay 30 holds when relay16 is operated. l/Vhen relay 16 releases after all of the pulsesoriginated by the dialing of the third digit have-been received, relay30 is released but relay 31 holds to the ground on lead 19. The releaseof relay 8O closes the operating circuit for relay 33 as hereinbeforedescribed. Relay 88 locks, causes the operation of relay 35, connectsthe pulsing circuit through brush 226 to the vertical magnet (not shown)of the final selector, connects'busy potential (battery through a lowresistance) to brush 22 1, and connects the winding of test relay 82through brush 223 to the sleeve brush of the final selector;

W hen the fourth and fifth digits of the called number are dialed thecircuit functions the same as hereinbefore described for a call to aline having a four-digit number,

Q is openedetthe ccntacts cfV ON springs 220 git number .qwere dialeds-except-cthat ithe L pass itl i'cugh -bjri shes 221-, 222,223 224,225

226 of switch instead of 2 through;

lyihcnmthe:trunl: 9; is "released one call-: cc'mpleteid lthi'cugh -tliebank of switch r switches M;an d','S -a 'e returned to normal as ,ofswitch T is then 0perated in an bvicus circuit to return the shaft anbrushes brushes 2 121 hereii befcredescribed. The releaseqmagiieti ofsWitchT mmmml. iUp cn reacli-ingtheir and:

' not required.

' A access-t0 the lines in an office ii-ftheabcve; n entiencdclass (M-the gswitch ,and its z fcrnial' zpositienf-the"circuitct magnet 229gncuiid is connected tQ- the inding layl n readinessfo the neXt caill.

ssscciazted' nmgnetsaind relay 230 aregnct requiizcd, and-Fig. 332tndthe N P-A- sp eggs are I tl ,t-11is\aPP i'-:a us and w rii-11g on/fitted,ztlie leads shown as ccn iecting' to t 3 the ncgrmally clcsedcontactscfYGN springs 22yane con; 'ecftecltolgcth'er, thezgleads shown as connectng t0v it:

back contactzand inner left-hand *z 'ifmatuire of relay, 280v arecc'nhaving live-digit iiected-togethe1y it-11d the, leads slicwn asicon-:1 I II access sliectiiig tQgthElblCkCOiltfiCt and ciite'r left-:hignd amiature-cfnelay 230cm ccnne'cted};

zlnisuch an olfice the lines having ib 5y Pe en by adiiili'ng cf thesecoiidedigit been: i

21 Qei'vied closes the circuit for operating relay @g et 28 :of switch Mstepst'hc brushesiiito gholdsvgandf l e-lay 3O Qr eleases when elay i et 111mm cat the-finals'electcz inding I of testf ela y 32 through brush"2 iii fiber a'r e di -alled the Jcjall isI-conipletediii the same fnia-ngici as I her :fcivs' call to a line having four-digit 1 an ofi'ice10%; class (a) p-except' tli pf ,thiiough v the bri shcs cfswitch S.

sF-c giviiig the trunk-offering 5 exceptlfthat 'ley'el; springs NP arenot -Iminals in :the bzink switch S and the lines anbers; 1 ye.from/9500 are acces ible t hi o'ugh I sets of temninalsin the Thank -0switchfM.

F vThe ,operaticn cf the distributor switches.

dig-it numbers whcse {first digit is the same as d zliiand S for callsto statiens'havihg four-digit 1;

numbers -2.:nd for calls to stations haiVing fivethe first digit off'SQZYLG :91 -ch e-I four-digit num- #cr'cttcd, endi elay 3 the-aboveinenticncd class (0);} The; cpei a e wre l toi vorm l a -the mp1t lybpI' :cperatejd; all as hereinheii thesec'o d digit sol.

' 28 20736 describec relay- 16 Q I the I linesfh vingi the five-digithum'hers', i.; e. r m 4L9;O0O t0 4 9,999 inclusive, areeccessible such311i iiafnner fas 'herei'nhejfo're .described fpr I calls o; imi a lynumbered lines in'igm oflifcefof the I c For" giving the; tiuti @9 5 2iriexiticnedclass 1 switches ,ST and 1 T and their: iasscciated ma;

n d Twining- --ajs] shown I in 'Fig, 31 1s vThe; leads VShQWn aconnecting-11c the leads v shpwi "as dd; 0 th \ontact with the ccrrespending=setrpfr=tf-1 12 1'23y1'12 3 fl 126w0f nlni in thepiaevio'uslyselected leV-elfz lhis i t. setv of terminals connects tossfinahselec'tcr ii Cl-i ;:h&S"- 1@C6SS to the line-cfjthc; celled IIBelay holds. and relay Q31; 0p

crates when relay 1-6v operates and relay 8L releases,- after} all oithe pulses oieigiiiated jhe-dialihgef the third digit have been -Tl".-.e"refleas ewof rem sc closes the {Relay I 33, 1lccl. s.=0 1acr atesrelay-35,, ccnnects tlie pulsing'll I 'g-h brush 26 to the Vertical meg-I -iil l cts. ;t0 h1-"'ush 24, and ccmiects the 8 0 the sleeve 111 11 10 2; the-iiinal I selec'tef. eiiihe tmu tha-Iidfitthdigits ofthc'ca'l-led I I OPGIitOI}. I w n li es in" an cfiice i the -above"shentioned class theI distfihuto switches v are arranged the sameasfcracofiicegof class,

irni shed, The lines having the hur -digit,- IlEIIlbBISiI-i e. .fl cm200O $021899 incli sive, are

fi ss bleth gh t e E k fsW t h, d f

h ugh th l k'OfSW Q .M-lo l t Em -N05 ffice are? Co leted in the} same"ii vacti g rthe bajc icont d i in 6ft Y. e ofr layfi e .w ec dj'wi r theeads shc nas COIlnQt iDg hQfl'lef s ck conta-c s d outerleiflhalidfarmaturefl25 f ted tcgethergand Fig.1

When the -third clig'itpis dialedxitary be r 'z scr b hum- $6 '5 I I Iat the." ,i0iis. ,ci r. c-uits to" andffiienithefinal selector pass ti-r-cugh thebri shes of switch lv'iiinstead' I offering 'opefgito'lg notpgthe l nes in gsnefllce' of the zibove vcN piingsiwsw were restored tonormal. The complete oper ation of relay 36 renders the NPA springs nalsoneach of the levels corresponding to the second digit, i. e. levels 1to 6 inclusive; and the lines having five-digit numbers, i. e.

7 67,000 to 69,999 inclusive are accessible through the sets ofterminals on the levels: which correspond to the seconddigit', i. e.levels 7 to 9 inclusive. 7

The dialing of the first digit 'steps'the '1 brushes up tothecorresponding level from which they arereturned to normal ashereinbefore described. The operation of level springs NPA when thefirst digit is dialed is ineffective. Relay 36 operated partially whentheshaft moved off-normal and operated completely when the shaft andbrushes effective if the second digit is such as to step the brushes upto the level orlevels on which these springs are actuated. In this eventthe release of relay 16, after all of the pulses V originated by thedialing of the second digit have been received and the brushes have beenstepped up to the correspondinglevel, closes a circuitfor operatingrelay 37. This circuit may betraced from battery through the righthandwinding and continuity contacts of rei lay 37, contacts of NPAsprings 39, frontv same manner as has hereinbefore been decontact andnext-to the-outer right-hand armature of relay 36, normally closedcontactsof, the continuity springs of relay 16, contacts of VON springs18, to ground on lead 19. Relay 37 locks, connects the winding of testrelay 32 to brush 24, and opens the circuit from the winding of relay43. The dialing of the third, fourth and fifth digits of the callednumber complete the connection-to theline of the called number in thescribed for'a call toa line havinga five-digit [number Whose first digitis the same as the first'digit of someof-the four-digit numbers inanoifice of'the above mentioned class (a). If the called number is afour-digit number the dialing of the second digit steps the" brushes up'to a level on which the NPA' springs are not actuated and relay 37 isnot foperated. The operation of relay 30, when I 'relay 16releases afterall of the pulses originatedby the dialing of the second digit have Ibeen r'eceivech-closes a circuit for operating relay. 43. This circuitmay be" traced' from "battery through the winding of relay 43,-back'contact and outer "right-hand armature of relay 37, front contact andinner right-hand armature of relay 36, backcontact and outer pright-hand armature of relay 16, front contact-and outer right handarmature of relay 30, contact'of'VON spring 18, to ground on lead 19.,The'opera-tion of relay 43 closeson' obvious circuit for operating relay31 and closes an obvious circuit for operating the rotary steppingmagnet -28ofswitch M. r The brushes ofswitch M are therefore advancedberm-site -dialin,'g;of-the'third digit into contact with the firstset-of terminals in the level which'corresponds to the second digit ofthe called IIHIIlbGL- This set of terminals con nects to a finalselector which has access to the line of the called number and the callis,

completed in the same manner as has hereinbefore been described for acall completed through the brushes of switch M to a line in an office ofthe above mentioned class.(a).

For giving the trunk-offering operator at -A access to the lines in anoilice of the above releases after all of the pulses originated by thedialing of the first digit have been received relay 37 is operated (onevery call) by the circuit through its right-hand winding. Relay 37looks and connects the winding of testrelay 32 to brush 24. Relay 36 isfirst partially operated and then completely operated operated and relay30 is operated and released as 'hereinbefore described. l/Vhen thesecond digit of the called number is dialed the brushes of switch M arestepped to the corresponding level. Relay 30 operates when relay'16releases after all of the pulses originated bythe dialing of the seconddigit have been received. l/Vhen the third digit is Idialed the rotarymagnet 28 is operated to step the brushes of switch M into contact 7with the corresponding set of terminals which connect to a finalselector having access to the line of the called number. WVhen relay16releases after all of the pulses originatedby the dialing of the thirddigit have been received relay 33 operates and the call is completed ascontrolled by the dialing of the fourth and fifth digits. of the numberin the same manner as hereinbefore described for a call to a line havinga five-digit number whose'first digit is the same as 'the first digit ofsome of the four-digit numbers in an'ofhce of the above mentioned class(a). v I

For giving the'trunk-oifering operator at A'access to the lines'inanofiice of the above.

mentioned class (i) switchS and its associatedmagnets andrelay-43 ofFig. 3 are'not furnished. but both'of the level springs NP and NPAare'furnished. The lines having numbersbeginning with a certain firstdigit, i. e., from 50,000 to 59,999 inclusive, are accessiblethroughfset's of terminals in' the bank of switch M and the NPA springsare actuated on the c'orresponding level. The lines having-numbersbeginningwith other first 18, to ground springs are 'l/Vhile "thedrawings digits, i. 6., from 60,000to 62,999 inclusive or from 48,999 to49,999 inclusive and from 60,000 to- 62,999 inclusive, are accessiblethrough sets of terminals in the bank of switch T and the NP springs areactuated on the corresponding level or levels. If the level to which thebrushes are stepped by the dial- 111g actuated relay 37 operates whenrelaylS releases after all of the pulses originated by the dialing ofthe first digit have been received; The call is completed through thebrushes of switch T in the same manner as hereinbefore described for acall to a line having a five-digit number whose first digit isdifi'eren'tiirom'the first digits ofthefourdigit numbers in an 'ofiiceof the above mentioned class (a).

If the level to which the brushes arestepped by the dialing of the firstdigit is that on which the NPA springs are actuated relay 37 is notoperated until relay 16 releases" after all of the pulses originated bythe dialing of the second digit have been received. The brushes'ofswitch M are returned to normal and relay 36 is partially and then comopletely operated in the same manner as hereinbefore described. Thedialing of the sec-v ond digit is effective to operate the verticalstepping magnet ofswitch M, and when relay 16 releases after all of thepulseshave been received relay 07 operates in the circuit irom batterythrough its'right-hand winding and continuitycontacts, contacts of NPAsprings 39, front contact and neXt-to-theouter right-hand armature ofrelay '36, nor:

contacts of the continuity springs of relay 16, contacts of VON springsonlead 19. The callis completed through the brushes of switch M in thesame manner 'asfhereinbe-fore described for a call toa linehaving afive-digit number whose first digit is the same as the first digit mallyclosed of some of the four-digit numbers in an office of the abovementioned class (a).

disclose the emboditrunk-ofii'ering disment of the inventlon lIl'ELtribute-r: circuit, the invention is not limited tosuch an arrangementand may be applied wherever selectlve operation of one or more switchesis desired in response to a number of control conditions which'maysormay not exceed the total number ofdifierent selective operations whichthe switch or switches are capable of efi'ecting 'withoutthe repetitionof one or more of the operations.

W/Vhat is claimed is: I I 1. In telephone system, lines having numberswhich are composed of a given number of digits, lines having numberswhich are composed of a 'difierent number of digits, an

" automatic switch, final selectors fdirectlyiac- 'cessible 'tosaid-switch, and means insaid switch responsive to pulses originated the[dialing of two or} more successive digits of the first digit is one onwhich the NP,

composed the number of said final selector'having access and meansinsaidfautomatic switch re; "sponsive to the dialing of the succeedingdigits of the number of said called line for of the number of a line toselect a final selector having access'to said line.

2. In a telephone system, a first group of lines having'numbers whichare composed of a given number of digits, a second group of lines havingnumbers which are composed or a difierent number of digits but which 7have the same first digit as the nun bers of some of the lines in saidfirst group, group of lines havingnumbers which are of said dififerentnumber of digits but which do not have thesame first digit as thenumbers of any of the lines in said first group, an automatic switch,final selectors directly accessible to said switch, and means in saidswitchresponsivel to pulses originated by the dialing of two or-moresuccessive digits of the number of a line to select a final selectorhaving access to said line. I

In a telephone system, a first group of lines having numbers which arecomposed of a given number of digits, a second group of lines havingnumbers which are composed of a difierent number of digits but whichhave the same first digit as the number of some of the lines in saidfirst group, an automatic switch, final selectors directly accessible tosaid switch, and means in. said switch responsive topulsesoriginated bythe dialing of two or more successive dlgits of the numa third i whichare composed v directly accesslble to spo nsive to pulses-originatedbythe dialing so i of two or more successive-diglts of the number of aline toselect apfinal selector: having access to said line. I

5. In a telphone system, a first group of lineshaving numbers which arecomposed of V a second group of d of a given number'of digits, lineshaving numbers which are compose said given number of digits but whichdo not digit as thelnumbers of any of the lines in said first group, anautomatic switch, final selectors directly 'accessible to said switch, acalled line, means "rehave the same first sponsive to the dialing ofsuccessive digits of i called line 7 to select a to said called line,

controlling said 'finaljselect-or to establish connection with saidcalled line. 7 V 6.'In a telephone system, lines having numbers composedof a given number 0 V, of said lines,

between the numbers of the lines in each of digits, an automatic switch,final selectors directly accessible to said switch, a called line, meansresponsive to the dialing of successive digits of the number of saidcalled line to select a final selector having access to said calledline, and means in said switch responsive to the pulses originated bythe dialing of the succeeding digits of the number of said called linefor controlling said final selector to establish connection with thesaid called line.

7. In a telephone system, lines having numbers composed of a givennumber of digits, lines having numbers composed of a different number ofdigits, an automatic switch, final selectors directly accessible to saidswitch, means for discriminating between numbers composed of said givennumber of digits and numbers composed of said different number ofdigits, and means responsive to pulses originated by the dialing of twoor more successive digits of the number of a line to select a finalselector having access to said line.

8. In a telephone system, a first group of lines having numbers whichare composed of a given number of digits, a second group of lines havingnumbers which are composed of a different number of digits but whichhave the same first digit as some of thenumbers of lines in said firstgroup, a third group of lines having numbers which are composed of saiddifferent number of digits but which do not have the same first digit asany of the numbersof lines in said first group, a main distributorswitch including a set of brushes and a terminal bank, means foradvancing the brushes of said main switch, final selectors directlyaccessible to said main switch, a secondary distributor switch in--cluding a set of brushes and a terminal bank, 'means for advancing thebrushes of said secondary switch, final selectors directly accessible tosaid secondary switch, a tertiary distributor switch including a set ofbrushes and a terminal bank, means for advancing the brushes of saidtertiary switch, final selectors directly accessible to said tertiaryswitch, means common to all of said switches for receiving pulsesoriginated by the dialing of successive digits of the number of any andmeans for distinguishing the other two. of said groups.

7 9. In a telephone system, lines, some of said lines having numberscomposed of a said-groups from the'numbers of the lines in given numberof digits, others of said lines having numbers composed of a difierentnumber of digits, a main distributor switch in cluding a'set of brushesand a terminalbank, means for advancing the brushes of said main switch,an auxiliary distributor switch including a set of brushes and aterminal bank, means for advancing the brushes of said aux:

iliary switch, means common to both of said switches for receivingpulses originated by the dialing of successive digits of the number ofany of said lines and for simultaneously controlling both of saidswitches, and means for distinguishing between numbers composed of saidgiven number of digits and numbers composed of said different number ofdigits.

10. In a telephone system, a first group of lines having numbers whichare composed of a given number of digits, a second group of lines havingnumbers which are composed of said given number of digits but whosefirst digit diiiers from the first digit of the numbers of all of thelines in said first group, a main distributor switch including a set ofbrushes and a terminal bank, means for advancing the brushes of saidmain switch, final selectors directly accessible to said main switch, anauxiliary distributor switch 1ncluding a set of brushes and a terminalbank, means for advancing the brushes of said auxiliary switch, finalselectors directly accessible to said auxiliary switch, means common toboth of said switches for receiving pulses originated by the dialing ofsuccessive digits of the number of a line in either of said groups,means for distinguishing between the number of a line in said firstgroup and the number of a line in said second group, and meansresponsive to pulses originated by the dialing of successive digits ofthe number of a line to select a final selector having access to saidline. 7 11. In a telephone system, lines having numbers which arecomposed of a given num ber of digits, lines having numbers which arecomposed of a diflierentnumber of digits, an automatic switch, finalselector directly accessible to said switch, means for distinguishingbetween numbers composed of said given number of digits and numberscomposed of said different number of dlgits, a called line, means insaid switch responsive to pulses originated by the dialing ofsuccesssive digits of the number. of said called line to select a finalselector having access to sald called line, and means in said automaticswitch responsive to the dialing of the succeeding digits of the numberof said called line for controlling said final selector to establishconnection with said called line.

.' 12. In a telephone system, a first group of lines having numberswhich are composed of a given number of digits, a second group of lineswhich are composed of a diflerent number of. digits, a main distributorswitch including a set of brushes and a terminal bank, means foradvancing the brushes of said main switch, final selectors connected tothe sets of terminals in the bank of said main switch, a secondarydistributor switch including aset of brushes and a terminal bank, meansfor advancing the brushes of said secondaryswitch, final selectorsconnected 'to the sets of terminals in the bank of said secondaryswitch, means for distinguishing between the numbers of linesinsaid-first group from the numbers of lines in said second group, acalled line, means responsive to pulses originated by the dialing ofsuccesswitch, final selectors connected to the sets sive digits of thenumber of said called line to select a final selector having access tosaid called line, and means in and common to said distributor switchesresponsive to the pulses originated by the dialing'of the succeedingdigits of the number of said called line for controlling said finalselector to establish connection with said called line."

13; In a telephone system, a first group of lines having numbers whichare composed of a given number of digits,;a second group of of terminalsin the bank of'said secondary switch for distinguishing a call'to'a linein said second group, a called line, means responsiveto'pulsesoriginated by the dialing of two or more successive digits ofthe number of a lineto select a final selector having access to saidline, and means in'andcommon ,to said distributor switches responsive tothe pulses originated by the dialing of the succeeding digits ofthenumber of saidcalled line for controlling said final selector toestablish connection with said called line.

14:. In a telephone'system, a first groupof lines having numbers whichare composedof a given number of digits, a second group of lines havingnumbers which are composed of difierent number of digits, a two-motiondistributor switchvincluding a set of brushes Y and a terminal bank,final selectors connected to the sets of terminals in said bank, acalled line, means responsive to the dialing of adigit of the'number' ofsaid called line for advancing said brushes in a vertical movement,means for returning said brushes to normal after said vertical movement,means responslve to the dlallng' of the first succeeding digit of thenumber of said called line for advancing the brushes in a second verti-"l-ectors directlyaccessible to said main switch,

cal movement, means including contacts actuated on certain levels ofsaid switch for distinguishing calls to lines in said second group,means effective without further dialing to advance saidvbr'ushes in arotary movement into contactwvith a set of terminals.

which are connected to a final selector having access to said calledline if sald called lineis in said first group, means responsive to afinal selector having access to said called the dialing of the secondsucceeding digit of the numberof said calledlin e for, advancing saidbrushes into contact with thecorresponding set of terminals which areconnected to line if said called line is in said second group, means 1nsaid swltch responsive to the pulses originated by the dialing of thethirdsucceeding and the remaining-digits ofthe number of said calledline for controlling the final nected to establishconnection with saidcalled line if said called line is in said second group,

and means in said switch responsive to the pulses originated by thedialing of the sa1dsecond succeeding and the remaining digits of saidcalled line for controlling the final selector to which the said brushesare conselector to which the said brushes are 'connected to establishconnection with said called line if said called line is in said firstgroup;

15 Ina telephone'system, lines composed of a given number of digits,atwo-motion auterminal bank, means for advancing said brushes in avertical movement,means for advancing said brushes in a rotary movement,final selectors connected to the sets ofterminalsin said bank, a calledline, means respontomatic switchincluding a set of brushes and asivetothe dialing ofa digit of the number of I saidcalled line foradvancing said brushes in a Vertical. movement, means for returning saidbrushes to normal after said vertical movement, means responsive tothedialing of I a the first succeeding digit of the number of saidcalled'lin'e for adv'ancing said brushes'in a second vertical movement,means respons'ive'to the dialing of the second succeeding digitof thenumber of said called line for" advancing the brushes in a rotarymovement into'contact witha setof terminals whichare connected to afinal selector having access to said called-line, and means in saidautomatic switch responsive to the pulses-originated by the dialing oftheremaining' digits lot the number of said'calledline forcontrollingsaid final selector to establish connection with said calledline. V

Inla telephone system, a first group oflmes having numbers which arecomposed o'fa glven number of dlg ts, a secondgroup oflines havingnumbers which are composed fof said given number of digitsbut whosefirst 'Ydigit differs from the first digit of the number of any; of thelines in said first group, a twomotion main distributor switch includinga; set of brushes andaterminalbank, final sea'two-motion auxiliarydistributor switch including a set of brushes and a terminal bank,

final selectors directly accessible to said aux-H. iliary switch, meanscommon to both switches for receiving pulses originated by the dialingof successive digitsof the-numberof a line in either of said groups, acalled l1ne, means res sponsive tothe dialingv of a digit of the 'numherof said called line, for advancing the brushes of said main switch in avertical movement, means including contacts actuated on certain levelsof said main switch for distinguishingthe number of a line in saidsecond group, means for returning the brushes of said switch to normalafter said vertical movement, means responsive to the dialing of thefirst succeeding digit of the number of said called line if said calledline is in said secondgroup for advancing the brushes of said mainswitch one step in a second vertical movement and for advancing thebrushes of said auxiliary switch in a first vertical movement to thelevel corresponding to the said first succeeding digit, means responsiveto the dialing of the second succeeding digit of the number of saidcalled line for advancing the brushes of said auxiliary switch in arotary movement into contact with a set of terminals which are connectedto a final selector having access to said called line it said calledline is in said second group, means responsive to the dialing of thefirst succeeding digit of the number of said called line if said calledline is in said first group for advancing the brushes of said mainswitch in a second vertical movement to the level corresponding to thesaid first succeeding digit, and means responsive to the dialing of thesecond succeeding digit of the number of said called line for advancingthe brush-es of said main switch in arotarymovement into contact with aset of terminals which are connected to a final selector having accessto said called line if said called line is in said first group.

17. In a telephone system, a first group of lines having numberscomposed of a given number of digits, a second group of lines havingnumbers composed of a different number of digits, a two-motion maindistributor switch including a set of brushes and a terminal bank, finalselectors directly accessible to said main switch, a two-motionsecondary distributor switch including a set of brushes and a terminalbank, final selectors directly accessible to said secondary switch,means common to both of said switches for receiving pulses originated bythe dialingoi successive digits of the number of a line in either ofsaid groups, a called line, means IGSPOIlSlVGlO the dialing of a digitof the number of said called ter said vertical movement, meansresponsive "to the dialing of the first succeeding digit of 'thenumberof said called line for advancing .the brushes of said main switch in asecond line for advancing the brushes of both of said switches inavertical movement, means for returning the brushes of saldmain switchatvertical movement and for advancing the brushes of said secondaryswitch into contact with a set of terminals corresponding to said firstsucceeding digit, a final selector connected to said terminals forgiving access to said called line if said called line is in said to thedialing of the second succeeding digit,

of the number of said called line if said called line is in said secondgroup for advancing the brushes of said main switch in a rotary movementinto contact with a set of terminals which are connected to a finalselector having access to said called line.

18. In a telephone system, a first group of lines having numberscomposed of a given number of digits, a second group of lines havingnumbers composed of a different number of digits, a two-motion maindistributor switch including a set of brushes and a terminal bank, finalselectors directly accessible to said main switch, a two-motionsecondary distributor switch including a set of brushes and a terminalbank, final selectors directly accessible to said'secondary switch,means common to both of said switches for receiving pulses originated bythe dialing oisu ccessive digits of the number of a line in either ofsaid groups, a called line, means responsive to the dialing of a digitof the number of said called line for advancing the brushes of both ofsaid switches in a vertical movement,

means including contacts actuated on certain levels for distinguishingthe number of said called line if said called line is in said secondgroup, means for returning the brushes of said main switch to normalafter said vertical movement, means responsive to the dialing of thefirst succeeding digit for advancing the brushes of said main switch ina second vertical movement to the corresponding-level, means responsiveto the dialing of said first succeedingdigit for advancing the brushesof said secondary switch in a rotary movement into contact with thecorresponding set of terminals if said called line is in said firstgroup, and means responsive to the dialing of the second succeedingdigitfor'advanc- 7 ing the brushes of said main switch into con-

